1. Field of the Invention
This invention relates generally to exercise apparatus, and more particularly it relates to apparatus in which the energy of exercising is imparted to a flywheel as angular momentum and which is useful for a variety of exercises and for use in a large variety of different positions.
2. Description of the Prior Art
It is old in the art to exercise by placing a number of heavy objects on a bar and then lifting the bar against the acceleration of gravity to perform a variety of different exercises. A large variety of exercises may be performed to exercise various muscles of the body. Since different muscles require different varieties and magnitudes of exercise, it is necessary to change the weights on a bar during an exercise period in order to provide a well rounded exercise program.
It is also well known to exercise by applying forces exerted by muscles in the body against some fixed resistence, such as the friction pads in a rowing machine or the springs of a pull on grip.
The use of heavy weights in the usual home is unsatisfactory for a number of reasons. They must be used in an area where nothing will be damaged if a weight is accidentally dropped, the floor must be one which will withstand damage by the weights, and storage is difficult. Weights are also found unsatisfactory because of the necessity of lowering weights once they have been lifted. The user does not build strength lowering a weight, but lowering weights does burn up energy and saps his strength. Thus, in lifting weights the user must retain enough strength to lower the weight once it has been lifted. Presence of the weight at the end of the lift is particularly objectionable in such lifts as a bench press, where the user lies with his back on a bench and presses the weight upward. It may be necessary to have two helpers present to lift the weights on and off. Additionally in order to perform a well rounded exercise program with weights, it is necessary to have a number of pieces of equipment, such as, for example, a bench for bench presses and a rack to receive the weights for various exercises.
The use of the fixed resistance, such as pulling against the frictional drag in a rowing machine, is also unsatisfactory for a number of reasons. The equipment tends to wear out rather easily and frictional surfaces in the equipment must be refinished or replaced.
More importantly the force exerted by a constant frictional resistence differs from the force exerted on a weight by gravity. Gravity is an accelerative force and the mass of the weights to be lifted possesses inertia. An inertial mass being lifted in an accelerative field such as a gravity field has lift characteristics that are very different from the lift characteristics provided by a fixed resistance such as a frictional stop or spring, which exert the same resistance at all times or an increasing resistance. A weight will be initially very difficult to lift, requiring a maximum effort and, once this initial inertia has been overcome and the weight begins to move, it will tend to keep moving, thus making completion of the lift easier and allowing a greater weight to be lifted. This inertial resistance also differs from the resistance provided by a spring. A spring, by Hooke's law, is initially easy to compress or extend and grows more difficult to compress or extend as extremes of compression or extension are attained. Compressing or extending a spring thus provides the opposite resistance characteristic from lifting a weight under the acceleration of gravity.
Thus none of the common substitute exercises for the lifting of weights attached to a bar in a gravity field substantially duplicate the effect of such weight lifting on a exerciser's muscles, i.e., that of a inertial resistence followed by accelerative resistance, as does the lifting of weights.